1. Field of the Invention
The present invention relates to a technique for handling an image including characters, symbols, and the like.
2. Description of the Related Art
The invention described in Japanese Patent Laid-Open No. 3-174658 implements extraction of a logo region by paying attention to the singularity of the logo color, but does not mention about a logo search. The invention described in Japanese Patent Laid-Open No. 10-171826 conducts a similar image search using image objects.
However, such prior arts implement a non-strict search using image feature amounts, and do not strictly search a logo. In order to search for a single logo mark in detail, after an object search is conducted, simple template matching is required. However, such technique does not cover any logo formed by a plurality of objects whose regions stick together (such state occurs when text regions are interlaced) at times or are separate from each other at other times.
In this way, as for a logo (e.g., family crest of paulownia) extracted as a single object, an image feature amount search or template matching for respective objects is conducted. However, in case of a logo which does not form one cluster, i.e., a text-based logo, objects are extracted for respective characters, and such characters may be recognized by an OCR or may not be recognized and handled as images since they are design characters. Therefore, there is no effective search method.
Therefore, the problem is to implement a technique that conducts a logo search robust against a logo from which objects are extracted for respective characters in case of a logo which is extracted as a single object, and a logo that does not form one cluster, i.e., a text-based logo.
The present invention has been made in consideration of the a forementioned problems, and has as its object to provide a technique that allows a robust search for a logo in an image.